Automatic idle speed-up device



Feb. 14, 1967 M. J. THOMAS 3,

AUTOMATIC IDLE SPEED-UP DEVICE Filed Aug. 13, 1964 2 Sheets-Sheet 1MICHAEL J. TH AS //VVEN A T TORNEVS Feb, 14, 1967 M. J. THOMAS 3,304,068

AUTOMATIC IDLE SPEED-UP DEVICE Filed Aug. 13, 1964 2 Sheets-Sheet 2MICHAEL J. THOMAS INVENTOR.

A 7' TO/PNEVS United States Patent Ofiice 3,394,968 Patented Feb. 14,1967 3,304,068 AUTOMATIC IDLE SPEED-UP DEVICE Michael J. Thomas,Dearborn, Mich., assignor to Ford Motor Company, Dearborn, Mich., acorporation of Delaware Filed Aug. 13, 1964, Ser. 389,322 6 Claims. (Cl.26141) This invention relates to a charge forming device for an internalcombustion engine and, more particularly, to a charge forming deviceembodying an automatic idle speed-up that prevents the engine fromstalling when unusually high loads are placed upon it at idle.

The internal combustion engines that power motor vehicles are calledupon to drive numerous accessories. Such accessories as power steeringpumps and air conditioning compressors place a considerable load uponthe engine. In many instances, the driving load of these accessories isthe greatest during engine idle operation. For example, the output loadof a power steering pump is greatest during parking maneuvering that isnormally done at idle speeds. The air conditioning compressor also mustcontinue to operate during long idle periods as are experienced in citytraflic driving. Most conventional engines do not develop suflicientpower at their normal idle speeds to drive these accessories at fulloutput. It is necessary, therefore, to provide some means to advance theidle speed when these accessories are being operated at their maximumoutput.

Many different forms of devices have been proposed to open the throttlevalve of the carburetor to increase idle speed during accessoryoperation. Although the systems have met with varying degrees ofsuccess, they are all somewhat unsatisfactory inasmuch as they operatethrough the throttle linkage. As a result, they must be adjustedfrequently and may, in some instances, interfere with normal throttleoperation.

It is, therefore, the principal object of this invention to provide anautomatic idle speed-up device that does not operate upon the throttlevalve of a charge forming device.

It is a further object of this invention to provide a supplemental fuelsystem for a charge forming device that automatically speeds up theengine to prevent stalling during idle.

A charge forming device for an internal combustion engine embodying thisinvention includes an induction passage. A throttle valve is provided tocontrol the flow through the induction passage. An idle dischargecircuit discharges fuel into the induction passage at a point contiguousto the idle position of the throttle valve. An idle speed-up dischargecircuit discharges additional fuel into the induction passage at a pointposterior to the throttle valve. The idle speed-up circuit includes apressure responsive valve member that controls the fuel discharge of theidle speed-up circuit. The pressure responsive member is responsive tothe pressure in the induction passage posterior to the throttle valveand is adapted to open when the induction system vacuum fails to exceednormal idle vacuum.

As a further feature of the invention, it is proposed to form the idlespeed-up circuit as a part of a spacer that is interposed between acarburetor and an intake manifold. The speed-up circuit communicateswith the fuel circuit of the carburetor and the pressure responsivevalve member is positioned in the spacer. This construction permitsmodification of the engine to embody the speed-up circuit with no otherchange than the addition of the spacer.

Further objects and advantages of this invention will become moreapparent when considered in conjunction with the accompanying drawings,wherein:

FIGURE 1 is a partial perspective view of an internal combustion engineembodying this invention;

FIGURE 2 is a top plan view of the spacer embodying the idle speed-upcircuit;

FIGURE 3 is a cross-sectional view taken substantially along the line 33of FIGURE 2;

FIGURE 4 is a cross-sectional view, in part similar to FIGURE 3, showingthe parts of the discharge circuit in another position.

Referring now in detail to the drawings, an internal combustion engineembodying this invention is indicated generally by the reference numeral11. The engine 11 includes an induction system comprised of an intakemanifold 12, a carburetor 13 and a spacer 14. The carburetor 13 andspacer 14 are secured to the intake manifold 12 with the spacer 14interposed between the carburetor 13 and the manifold 12 by a pluralityof studs 15 and nuts 16. A gasket 17 is positioned between the intakemanifold 12 and the spacer 14 and a gasket 18 is positioned between thespacer 14 and the carburetor 13.

A pair of induction passages are formed by the carburetor 13, spacer 14and intake manifold 12 for delivering a combustible charge to thecylinders of the engine. Each of the passages comprise a passage 19formed in the carburetor 13, a passage 21 formed in the spacer 14, and apassage 22 formed in the intake manifold 12. The induction passages 21and 22 are coaxially disposed. A throttle valve 23 is supported in thecarburetor induction passage 19 upon a throttle valve shaft 24 forcontrolling the flow.

The carburetor 13 may be of any conventional type that includes a fuelsource and fuel discharge circuits for delivering fuel to each of theinduction passages 19. The carburetor that has been depicted is of theFord two barrel type and is described in detail in the 1964 Ford ShopManual. The carburetor comprises an idle fuel circuit in addition to amain fuel circuit (not shown.)

The idle fuel circuit comprises an idle passage 25 that extends throughthe carburetor from the fuel bowl (not shown) to a point contiguous tothe normal idle position of the throttle valve 23 as shown in FIGURES 3and 4. The idle passage 25 is intersected by an enlarged transverselyextending passage 26 that is closed at its outer end by a plug 27. Idletransfer holes 28 extend from the enlarged passage 26 into the inductionpassage 19 at points above but closely spaced to the normal idleposition of the throttle valve 23. An idle discharge passage 29 extendsfrom the enlarged passage 26 toward the lower face of the carburetor 13.The idle discharge passage 29 is intersected by a horizontally extendingpassage 31 that terminates at an idle discharge port 32. An adjustableneedle valve 33 is positioned in the passage 31 for the adjustment ofthe idle fuel discharge.

During normal engine idle operation fuel will pass through the passages25 and 29 and out of the idle discharge port 32 into the inductionpassage 19. Air enters the'idle transfer holes 28 to mix with the idlefuel that is discharged. As the t-hrtotle valve 23 is opened from itsidle position, the idle transfer holes 28 are successively opened to theinduction system vacuum that exists below the throttle valve 23. As theidle transfer holes 28 are successively exposed to this vacuum, theywill cease to function as air bleeds and will discharge additional fuelinto the induction passage 19.

The idle circuit heretofore described will provide sufficient fuel fiowto maintain normal idle operation under most conditions. In the eventthat a greater load is positioned upon the engine it will tend to stall.An idle speedup circuit is provided to increase the rate of fuel and airflow into the induction system under this condition to prevent stalling.The idle speed-up circuit is indicated generally by the referencenumeral 34.

The idle speed-up circuit 34 is formed primarily in the spacer 14 andreceives its fuel from a fuel passage 35 that extends from the idlecircuit of the carburetor 13 through its lower face. A metering jet 36is positioned in the passage 35 to regulate the rate of fuel flow. Thepassage 35 opens into a cavity 37 formed in the upper face of the spacer14 through an aperture 38 in the gasket 18. A diagonally extending fuelpassage 39 interconnects the cavity 37 with a horizontally extendingbore 41. A speed-up discharge outlet 42 extends from the bore 41 to acavity 43 that is formed in the lower face of the spacer 14. The cavity43 is inopen communication with the induction passage 21 formed in thespacer 14.

The fuel discharge of the idle speed-up circuit is cont-rolled by ashuttle piston valve 44 that reciprocates in the bore 41. The pistonvalve 44 is normally biased by a coil spring 45 to an open position(FIGURE 3). The coil spring 45 is confined within the bore 41 by athreaded cap 46 that is received in the open end of the bore 41. The cap46 is slotted, as at 47, to permit adjustment of the preload on the coilspring 45 to regulate the operation of the piston valve 44.

The rear surface of the piston valve 44 is exposed to induction systempressure by the idle speed-up discharge outlet 42. During normal idleoperation, the induction system vacuum is relatively high and the pistonvalve 44 is drawn to the left to compress the coil spring 45 (FIGURE 4).Under this condition there will be no fuel discharge from the idlespeed-up circuit 34 because the piston valve 44 closes the fuel passage39. Should an engine driven accessory place an unduly high load upon theengine, induction system vacuum will decrease. The coil spring 45 willthen urge the piston valve 44 to the right (FIGURE 3). This opens thepassage 39 and permits the idle speed-up discharge circuit to experienceinduction system vacuum. Fuel will then be discharged from the dischargeoutlet 42 into the induction passage 21 to increase the engine idlespeed and stabilize engine operation. When the engine operation returnsto normal, the induction system vacuum will again draw the piston valve44 to the left to stop the fuel discharge.

Under some circumstances it may be desirable to bleed additional airinto the idle speed-up circuit for optimum engine operation. Toaccomplish this result, an air bleed passage 48 extends verticallythrough the spacer 14 and opens into the bore 41 at the rear of thepiston valve 44. The passage 48 has an enlarged mouth 49 that supportsball type valve 51. A wafer air filter 52 may be positioned across thepassage mouth 49 to retain the ball 51 in place and to filter theadditional air.

During normal idle operation the induction system vacuum will draw theball 51 upwardly (FIGURE 4) to close the air bleed passage 48. As theinduction system vacuum decreases due to an increased load on theengine, the ball 51 will fall opening the passage 48 and permittingadditional air to enter the idle speed-up discharge circuit (FIGURE 3).

The air bleed controlling valve may be designed to open when theinduction system vacuum fails to exceed any desired pressure by changingthe Weight of the ball 51. The pressure at which the piston 44 opens maybe varied by changing the-preload upon the coil spring 45. The air andfuel valves may be set to open simultaneously or sequentially asdesired. It is to be understood that the valves shown'are exemplary of apreferred embodiment of the invention. Other changes in the valves or inthe form that the idle speed-up circuit may take may be made withoutdeparting from the spirit and scope of the invention, as defined by theappended claims.

I claim:

1. A charge forming device for an internal combustion engine comprisingan induction passage, a throttle valve for controlling the flow throughsaid induction passage, an idle discharge circuit for discharging fuelinto said induction passage at a point contiguous to the idle posi-.tion of said thrott e valve, an idle speed-up discharge circuitcommunicating with said idle discharge circuit for dischargingadditional fuel into said induction passage at a point posterior to saidthrottle valve, an air passage communicating with said idle speed-updischarge circuit for bleeding air into said circuit for mixture withthe fuel discharged into said induction passage, and pressure responsivevalve means for controlling the air and fuel flowing into said inductionpassage through said idle speed-up discharge circuit, said pressureresponsve valve means being responsive to the pressure in said inductionpassage posterior to said throttle valve and being adapted to open whenthe induction system vacuum fails to exceed normal idle vacuum, saidpressure responsive valve means comprising a first valve member forcontrolling fuel flow and a second valve member for controlling airflow.

2. A charge forming device for an internal combustion engine comprisingan induction passage, a throttle valve supported in said inductionpassage for controlling the flow therethrough, a fuel source, an idledischarge circuit interconnecting said fuel source with said inductionpassage at a point contiguous to the idle position of said throttlevalve, an idle speed-up discharge circuit interconnecting said idledischarge circuit and said induction passage at a point posterior tosaid throttle valve, an air passage for bleeding air into said idlespeed-up discharge circuit for mixture with the fuel discharged intosaid induction passage, and pressure responsive valve means forcontrolling the rate of discharge of said idle speed-up dischargecircuit, said pressure responsive valve means being responsive to thepressure in said induction passage posterior to said throttle valve andbeing adapted to open when the induction system vacuum fails to exceednormal idle vacuum.

3. A charge forming device as defined by claim 2 wherein the pressureresponsive valve means comprises a first valve member for controllingfuel flow and a second valve member for controlling air flow.

4. An induction system for an internal combustion engine comprising anintake manifold, a carburetor, a spacer, means fixing said carburetorand said spacer to said intake manifold with said spacer beinginterposed between said carburetor and said intake manifold, saidcarburetor, spacer and intake manifold defining an induction passage, athrottle valve in said carburetor for controlling the flow through saidinduction passage, a fuel source in said carburetor, an idle dischargecircuit in said carburetor for discharging fuel from said fuel sourceinto said induction passage contiguous to the idle position of saidthrottle valve, an idle speed-up circuit extending from the idledischarge circuit of said carburetor into said spacer, said idlespeed-up circuit opening into the portion of the induction passagedefined by said spacer, and pressure responsive valve means forcontrolling the discharge of fuel from said idle speed-up circuit, saidpressure responsive valve means being responsive to the pressure in saidinduction passage posterior to said throttle valve and being adapted toopen when the induction system vacuum fails to exceed normal idlevacuum.

5. An induction. system for an internal combustion engine comprising anintake manifold, a carburetor, a spacer, means fixing said carburetorand said spacer to said intake manifold with said spacer beinginterposed between said carburetor and said intake manifold, saidcarburetor, spacer and intake manifold defining an induction passage, athrottle valve in said carburetor for controlling the flow through saidinduction passage, a fuel source in said carburetor, an idle dischargecircuit in said carburetor for discharging fuel from said fuel sourceinto said induction passage contiguous to the idle position of saidthrottle valve, an idle speed-up circuit extending from the idledischarge circuit of said carburetor into said spacer, said idlespeed-up circuit opening into the portion of the induction passagedefined by said spacer,

an air bleed extending through said spacer and opening into said idlespeed-up circuit for mixing air with the fuel discharged from said idlespeed-up circuit, and pressure responsive valve means for controllingthe air and fuel discharge of said idle speed-up discharge circuit, saidpressure responsive valve means being responsive to the pressure in saidinduction passage posterior to said throttle valve and being adapted toopen when the induction system vacuum fails to exceed normal idlevacuum.

6. An induction system as defined by claim 5 wherein the pressureresponsive valve means comprises a first valve member for controllingfuel flow and a second valve member for controlling air flow.

References Cited by the Examiner UNITED STATES PATENTS 2,615,696 10/1952Winkler 261-41 2,803,443 8/1957 Dillon an; 261 69 X 2,996,051 8/1961Mick 2 6F 69 3,042,387 7/1962 King 26141 3,146,844 9/1964 Carlson.

3,188,062 6/1965 Reid et al.

3,190,622 6/1965 Sarto 26169 X HARRY B. THORNTON, Primary Examiner.

T. R. MILES, Assistant Examiner.

1. A CHARGE FORMING DEVICE FOR AN INTERNAL COMBUSTION ENGINE COMPRISINGAN INDUCTION PASSAGE, A THROTTLE VALVE FOR CONTROLLING THE FLOW THROUGHSAID INDUCTION PASSAGE, AN IDLE DISCHARGE CIRCUIT FOR DISCHARGING FUELINTO SAID INDUCTION PASSAGE AT A POINT CONTIGUOUS TO THE IDLE POSITIONOF SAID THROTTLE VALVE, AN IDLE SPEED-UP DISCHARGE CIRCUIT COMMUNICATINGWITH SAID IDLE DISCHARGE CIRCUIT FOR DISCHARGING ADDITIONAL FUEL INTOSAID INDUCTION PASSAGE AT A POINT POSTERIOR TO SAID THROTTLE VALVE, ANAIR PASSAGE COMMUNICATING WITH SAID IDLE SPEED-UP DISCHARGE CIRCUIT FORBLEEDING AIR INTO SAID CIRCUIT FOR MIXTURE WITH THE FUEL DISCHARGED INTOSAID INDUCTION PASSAGE, AND PRESSURE RESPONSIVE VALVE MEANS FORCONTROLLING THE AIR AND FUEL FLOWING INTO SAID INDUCTION PASSAGE THROUGHSAID IDLE SPEED-UP DISCHARGE CIRCUIT, SAID PRESSURE RESPONSVE VALVEMEANS BEING RESPONSIVE TO THE PRESSURE IN SAID INDUCTION PASSAGEPOSTERIOR TO SAID THROTTLE VALVE AND BEING ADAPTED TO OPEN WHEN THEINDUCTION SYSTEM VACUUM FAILS TO EXCEED NORMAL IDLE VACUUM, SAIDPRESSURE RESPONSIVE VALVE MEANS COMPRISING A FIRST VALVE MEMBER FORCONTROLLING FUEL FLOW AND A SECOND VALVE MEMBER FOR CONTROLLING AIRFLOW.